Answer:
The vapor pressure of the solution is 23.636 torr
Explanation:
[tex]P_{solution} = X_{solvent}*P_{solvent}[/tex]
Where;
[tex]P_{solution[/tex] is the vapor pressure of the solution
[tex]X_{solvent[/tex] is the mole fraction of the solvent
[tex]P_{solvent[/tex] is the vapor pressure of the pure solvent
Thus,
15.27 g of NaCl = [(15.27)/(58.5)]moles = 0.261 moles of NaCl
0.67 kg of water = [(0.67*1000)/(18)]moles = 37.222 moles of H₂O
Mole fraction of solvent (water) = (number of moles of water)/(total number of moles present in solution)
Mole fraction of solvent (water) = (37.222)/(37.222+0.261)
Mole fraction of solvent (water) = 0.993
Note: the vapor pressure of water at 25°C is 0.0313 atm
Therefore, the vapor pressure of the solution = 0.993 * 0.0313 atm
the vapor pressure of the solution = 0.0311 atm = 23.636 torr
Answer:
0.0310 atm.
Explanation:
The vapor pressure of water at 25°C is 0.0313 atm.
Number of moles:
NaCl
Number of moles = mass/molar mass
Molar mass of NaCl = 23 + 35.5
= 58.5 g/mol.
Moles = 15.27/58.5
= 0.26 mol.
Water:
Molar mass = (1*2) + 16
= 18 g/mol
Number of moles = mass/molar mass
= 670/18
= 37.22 mol.
Using Raoult's law,
Mathematically,
Psol = Xsolv * P°solv
Where
Psol = vapour pressure of the solution
Xsolv = mole fraction of the solvent, water.
P°solv = vapour pressure of the solvent, water
Mole fraction of a substance in a solution is the ratio of its moles by the total number of moles in the solution.
Xa = moles of a/(moles of (a+b)
Xwater = 37.22/0.26+37.22
= 0.993
Psol = 0.993 * 0.0313
= 0.0310 atm
